A capacitive device such as a Coriolis-based gyroscope transducer, outputs a capacitive signal indicative of measurements or other properties of the capacitive device. Subsequent signal conditioning for such devices can be more efficient by first converting the capacitance signal to a voltage signal. For an example of a Coriolis-based gyroscope transducer, the capacitance signal can be an amplitude modulated signal that occupies a narrow range of frequencies around the mechanical resonance of a “Drive” element of the gyroscope. An envelope of the amplitude modulated signal can correspond to a desired signal and an amplitude modulated demodulator can extract the envelope of the signal.
However, several sources of error can corrupt extraction of the desired signal. Non-zero delay in the signal conditioning path prior to demodulation can cause signal leakage. Leakage on the sensitive sense nodes (e.g., the input to an interface circuit for converting the capacitance signal) can reduce the output range of the circuit. Both leakage and delay often depend on temperature such that leakage compensation and delay can be competing performance metrics. One known approach employs a resistor feedback in conjunction with a capacitance-to-voltage circuit to process the capacitance signal. However, this method requires a large value resistor to produce a small phase error, which makes the capacitance-to-voltage conversion more susceptible to leakage. Generally, known capacitance-to-voltage conversion interface circuits are susceptible to high noise, electromagnetic radiation and/or electrical fields.
In view of the above, there is a need for capacitance-to-voltage interface circuits and related methods of operation that address one or more of the above concerns, or other concerns, associated with capacitance-to-voltage interface circuits, and/or provide one or more advantages by comparison with known capacitance-to-voltage interface circuits.